EDIT : It looks like he does not have any of the 2 diodes he uses placed on the heatsink so I guess it is not really needed.

nattawa

27th July 2012 06:46 PM

3 diodes and you're over compensating, and 4 is way over what you need. You may want to leave the 4th off the heat sink to be sure of staying in class A and avoiding under biasing at higher temperature conditions.

I would not load the op amp up with a low-ish 750-ohm resistance and degrade the performance for nothing. A constant current source should be a good replacement for the R2 and R7 for me.